Process of treating iron, cast-iron, and steel.



Patented April 25, 1905.

lJNlTED STATES PATENT @rrica JEAN LEUARME, OF PARIS, l llANtJ-l PROCESS OF TREATING IRON, CAST-IRON, AND STEEL.

SPECIFICATION forming part of Letters Patent No. 787,926, dated April 25, 1905.

Application tiled October 3, 1903. Serial No. 175,681.

1'0 (0H 1141/0112 it may concern/.-

Be it known that I, JEAN LECARME, a citizen of France, residing at 118 Rue de Vaugirard, Paris, France, have invented new and useful Improvements in Processes of Treating lron, Cast-iron, and Steel Employed in the Manufacture of Various ()bjects, Tools, and Sonorous Musical Instruments, of which the following is a specilication.

The process forming the object ol the pres ent invention is applicable to articles made of iron, cast-iron, or steels not capable of being hardened by tempering. it has for its object to give to these articles new qualities ol' hardness. tenacity, and others either througlmut their entire mass or only to a certain thickness and over the entire surlace or only over a part thereol' and to render them capable ol beingtempered. This result is obtained by incorporating with the surl'ace ol' the metal and to variable depth a body chosen to modil'y in a convenient way the qualities of the primitive metal. Articles can thus be made in cast-iron, iron, or mild steel, whicn are easy to work, and they can then have given to them over their entire surl'ace or only over determined parts the qualities sought of hardness, tenacity, sonorousness. &c.

The process consists in covering the pieces to be treated or only determined parts of said pieces with a composition containing the body to be incorporated and in heating said pieces to a bright red in a mullle or in boxes tilled with wood-charcoal in powder or with sand or in any suitable way excluded trom the air. The composition employed for this purpose has for its base a mixture of woodcharcoal in line powder and a cyanid or i'errocyanid, to which is added an agglutinant material, such as gelatin or dextrin, and the whole is made into a paste, with which the pieces to be treated are coated either entirely or partially.

\Yhen it is desired simply to produce on the surface of the article in iron a layer of normal steel that is to say, when it is desired to cement it the cyanid or t'errocyanid of potassium is employed, according as it may be desired to have a more or less energetic action.

hen it is desired to obtain on the surlace ol" iron a layer of special steel by the incorporation of a metal such as nickel, chromium, manganese, &c., the cyanid of potassium will be replaced by the cyanid of nickel, ol chromium of manganese, &c., or else to the cyanid ol potassium will be added a salt or an oxid ot the metal which is desired to be incorporated. There can thus be obtained articles having superficially all the qualities of nickel steel, chrome steel, or manganese steel.

Tools made o'l nickel steel which do not acquire by tempering sullicient hardness may be treated by the process above described with a view to incorporate with them superficially dill'erent metals or mctalloids suitable tor the purpose to which the article is to be applied. Excellent tools are thus economic-ally obtained which never break in tempering. This method applied to the construction of rotary cutters, screwtaps, &c., is particularly advantagtmus.

Finally, compounds can be obtained which are endowed with very various properties by incorporating with them metalloids, such as sullur, phosphorus, arsenic, nitrogen, &c. These bodies are ordinarily eliminated as much as possible in metallurgy, because they render irons and steels brittle and unsuitable for use in factories; but by incorporating them a'lter manul'acture they can give advantageous results in certain applications. These bodies themselves or their acids will be added to the mixture ol' charcoal and cyanid. The ilollowing example is a composition which would be suitable to obtain a layer of steel slightly arsenious: charcoal linely pulverized, 'l'crrocyanid of potassium. pulverized, arsenious anhydrid, (traces,) boiled linseed-oil, siccative oil o'l turpentine. This mixture em ployed in the form of paint gives excellent results 'l'or example, on rotary cutters made of mild steel.

The properties obtained by this process are capable oi giving rise to applications en tirely now in industry. Thus iron and steel acquire a remarkable sonorousness, the timber or tone-of which varies with the body incorporated and the depth of the layer incorporated. Thus bells, clock-bells, and other sonorous instruments may be made of iron or steel which may be worked with ease and afterward have given to them the hardness and the tone desired by incorporating with them, as above described, the bodies proper to obtain the result sought. Finally, the power of acting on the piece only partially, and even of obtaining on the same piece portions more or less hard and of different qualities, can in certain cases considerably simplify the manufacture.

Having fully described my invention,what I claim, and desire to secure by Letters Patent, is-

The process for hardening and transforming into steel of variable qualities the entire or part of the surface of objects, rotary cutters, screw-taps and other tools and bells and other sonorous instruments made of iron, cast-iron, or mild steel, said process consisting of coating the objects on the surfaces or parts to be treated with a composition containing charcoal in powder, cyanid of potassium, and a combustible agglutinant body and then heating these bodies to a bright red excluded from the air, substantially as herein set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing witnesses.

JEAN LECARME.

Witnesses:

WILLIAM J. MURRAY, PAUL T. PA UET. 

